* Android Resolver: Fixed warning about missing Packages folder when loading
  XML dependencies files in versions of Unity without the package manager.
* Android Resolver: Fixed resolution window progress bar exceeding 100%.
* Android Resolver: If AndroidX is detected in the set of resolved libraries,
  the user will be prompted to enable the Jetifier.
* Android Resolver: Improved text splitting in text area windows.
* iOS Resolver: Added support for Unity's breaking changes to the Xcode API
  in 2019.3.+. Cocoapods are now added to build targets, Unity-iPhone and
  UnityFramework in Unity 2019.3+.

Change-Id: Ib9a602aa7b596a2a1204b806fb407e984ca695b1

Unity's labels can only display a limit number of characters so the
text area window splits text into multiple label elements.  The splitting
was not taking into account line breaks so text would be split at very
odd boundaries making things harder to read.  This changes the line
splitting to preferably occur on line breaks.

Change-Id: I59d8fc897856da336df19a3324da313fb670b240

AndroidX doesn't compile with API level < 28 which results in a cryptic compile
error for developers who haven't installed API 28 in their Android SDK or
selected a lower API level for compilation in Unity. This detects AndroidX
libraries when using Gradle resolution - this isn't possible at the moment for
transitive dependencies when using the mainTemplate.gradle patcher - and
prompts the user to fix their build configuration otherwise resolution is
aborted.

This also fixes cases of multiple completions in LabelAssets and the AAR
processing code.

Bug: 136120351
Change-Id: I052c69fd8abdb8d991e5777fc64a1e3d30cf9ca9

Unity 2019.3 adds support for using Unity as a framework on iOS which
broke the method of retrieving the main application target in the
Xcode API. This patch changes the iOS resolver to fetch the Xcode targets
using the legacy API, falling back to the new API if it's available.

Bug: 136038764
Change-Id: I2236b4cfa08f64feb6e6a7957d71987cdacaa6a9

Package manager was broken by b61a712f

Change-Id: I56f7e93f217427aff2b74cbc7633e782c50350f0

XML dependency loading now only searches directories that exist to workaround
the asset database returning a warning about the Packages directory being
missing.

This also fixes the progress bar display exceeding 100%, it will now clamp
to 100% instead.

Fixes #244
Bug: 135916383

Change-Id: I8eb25927d8977e33b35902fab3d2e5ecd3de7345

* Android Resolver: Added support for loading *Dependencies.xml files from
  Unity Package Manager packages.
* Android Resolver: Resolution window is now closed if resolution runs as
  a pre-build step.
* iOS Resolver: Added support for loading *Dependencies.xml files from
  Unity Package Manager packages.
* Android Resolver: Fixed generation of relative repo paths when using
  mainTemplate.gradle resolver.
* Android Resolver: Fixed copy of .srcaar to .aar files in repos embedded in a
  project when a project path has characters (e.g whitespace) that are escaped
  during conversion to URIs.
* Android Resolver: Fixed auto-resolution always running if the Android SDK
  is managed by Unity Hub.

Change-Id: I243e7c7cc1e41e8e847561c0a214e8adbb1e8899

This closes the Android Resolver window when resolution occurs during build.
In addition, this commit deletes a load of stale code moving everything from
DefaultResolver to the GradleResolver class in the process.

Bug: 135951368
Fixes #238

Change-Id: I01555be6b4b8bdf3b1d726340fd543d3d9a49a97

When Unity Hub manages the Android SDK installation, Unity's Android editor
plugin does not return the managed SDK path when the Android Resolver
DLL is loaded.  Instead, the Unity's Android editor plugin will return the
managed SDK path after the first editor update.

Since the static initialization order is non-determinstic, this changes all
property polling in the Android Resolver to defer fetching the initial value
of properties until the first execution of EditorApplication.update.

Bug: 134518417
Change-Id: Ief8dd6d0e790dee1bbb91ed2b2c2fa8ac3c529aa

Bug: 135916383
Fixes #236

Change-Id: I31114ae640d3f57a810298966b859ab65597c26e

Bug: 135916453
Fixed #240

Change-Id: Iad71a057704c5789e2c5d81b8bc483b145aadc91

* Android Resolver: Fixed error reported when using Jetifier integration
  in Unity 2018+ if the target SDK is set to "highest installed".

Change-Id: I345846e998c8182c3b00b00aed810025c51d9793

Some internal APIs we're using to retrieve the latest installed Android SDK
changed in Unity 2018 and beyond.  This patch fixes methods used to retrieve
the installed Android SDK so that we can validate whether Jetpack can be
used with the selected build target.

https://github.com/googlesamples/unity-jar-resolver/issues/145
Bug: 135263921
Change-Id: I14bc8a7d6995089b28bfd712eda2d6b29cbc2597

* Android Resolver: Added initial
  [Jetifier](https://developer.android.com/studio/command-line/jetifier)
  integration which simplifies
  [migration](ttps://developer.android.com/jetpack/androidx/migrate)
  to Jetpack ([AndroidX](https://developer.android.com/jetpack/androidx))
  libraries in cases where all dependencies are managed by the Android
  Resolver.
  This can be enabled via the `Use Jetifier` option in the
  `Assets > Play Services Resolver > Android Resolver > Settings` menu.
  Caveats:
  - If your project contains legacy Android Support Library .jar and .aar
    files, these files will need to be removed and replaced with references to
    artifacts on Maven via `*Dependencies.xml` files so that the Jetifier
    can map them to Jetpack (AndroidX) libraries.
    For example, remove the file `support-v4-27.0.2.jar` and replace it with
    `<androidPackage spec="com.android.support:support-v4:27.0.2"/>` in a
    `*Dependencies.xml` file.
  - If your project contains .jar or .aar files that use the legacy Android
    Support Libraries, these will need to be moved into a local Maven repo
    [See this guide](https://maven.apache.org/guides/mini/guide-3rd-party-jars-local.html)
    and then these files should be removed from your Unity project and instead
    referenced via `*Dependencies.xml` files so that the Jetifier can
    patch them to reference the Jetpack lirbaries.

Bug: 113575309
Change-Id: I83723cb5b2eaa4369beb454e498202285758af56

Added integration tests for the internal build system and
mainTemplate.gradle resolution modes when using the Jetifier.

https://github.com/googlesamples/unity-jar-resolver/issues/145
Bug: 135263921
Change-Id: I5c636050e29a2232755aa70049f82e4c51c45fc1

Auto-resolution was previously relying upon polling for differences in
runtime state which could break if the DLL was reloaded after settings
are changed.  This commit stores the resolution settings with the rest
of the state from the last resolution so that it's possible to
auto-resolve if any of this state changes or the settings change that
require resolution.

Bug: 135263921
Change-Id: I5858cebdb905f6425faee719032b830c9a066a81

This adds an option to enable Jetpack (AndroidX) Jetifier processing as
part of the either dependency resolution or Gradle builds.

This change also ensures that the user is notified of build environment
settings that will prevent the Jetifier from functioning or prevent the
use of the Jetpack (AndroidX) libraries.
See...
- https://developer.android.com/studio/releases/gradle-plugin#3-2-0
- https://developer.android.com/jetpack/androidx#using_androidx

https://github.com/googlesamples/unity-jar-resolver/issues/145
Bug: 135263921
Change-Id: Iddb2ab7e34b411973c761360e485aed2506f2ddc

The Jetifier requires the data binding library version to use, which is
the same version as the Android Gradle Plugin version. This commit
exposes a property which parses the Android Gradle Plugin version from
the Gradle build templates provided by Unity.

Bug: 135264177
Change-Id: I7780868d88d1810e615204abd820ddef348f7f11

Developers tend to move the plugin around in their project. However,
the Google.VersionHandler.dll asset GUID was changing with each release
resulting in the DLL failing to load if multiple versions are present in
the project. This patch fixes this issue by only generating new GUIDs
for files that are renamed in the plugin.

Bug: 127793909
Change-Id: I4569e467f3f0c1f96722a280d62af5916344af3e

com.android.support:multidex does not use the same versioning scheme
as other legacy Android support libraries so it should not be
version locked.

Bug: 135276990
Fixed #234

Change-Id: Idf567388cec68fca022022d14819df56a576254b

Added Jetifier support to the Gradle artifact downloader script.
download_artifacts.gradle can now substitute direct and transitive
dependencies on the legacy support libraries to Jetpack and rewrite
references to the legacy support libraries in all downloaded libraries.

This adds unit and integration tests for this functionality but does not
yet connect this to the Android Resolver Unity plugin.

https://github.com/googlesamples/unity-jar-resolver/issues/145
Bug: 113575309
Change-Id: Ibb92e43751425ebfd7cedfae62d275099860aaaa

This is required to use Kotlin plugins like the Jetifier with
Gradle's embedded Kotlin runtime.

https://github.com/googlesamples/unity-jar-resolver/issues/145
Bug: 113575309
Change-Id: I4d11d30d7944fb95a2c1c2f19f0762d55eda0024

Gradle now runs task execution in parallel by default but due to
https://github.com/gradle/gradle/issues/6068 it's not possible
to capture stdout / stderr from individual tasks which breaks
download_artifacts_test.gradle.  This commit modifies the test to run
all tasks serially, prepares for the Gradle bug to be fixed and
cleans up the output a little when tests fail.

https://github.com/googlesamples/unity-jar-resolver/issues/145
Bug: 113575309
Change-Id: Ifee400beaa4544b3d9145cce51b69125ffc1f5b9

* Android Resolver: Fix copying of .srcaar to .aar files for
  mainTemplate.gradle resolution.  PluginImporter configuration was previously
  not being applied to .aar files unless the Unity project was saved.

Change-Id: I597799035d928af3aad53e6c6ebc63bb14f47749

After modifing PluginImporter settings, assets need to be reimported
for the changes to be applied in some versions of Unity.

Reported in https://github.com/firebase/quickstart-unity/issues/377

Bug: 135125825

Change-Id: I6ca17391d3f89f213a8a21bea6613d3321ed7386

The warning has no context (i.e where the repo is referenced) and hence
only adds spam to the log.

Change-Id: I54588ac845ff35b235bea60e6bf1252a65db9c39

* Android Resolver: Fixed resolution of Android dependencies without version
  specifiers.
* Android Resolver: Fixed Maven repo not found warning in Android Resolver.
* Android Resolver: Fixed Android Player directory not found exception in
  Unity 2019.x when the Android Player isn't installed.

Change-Id: Idd553b1920975797ae9ffe97c8792b6fd7e2c5a9

Executing commands with POSIX paths fail on Windows, this
modifies the CommandLine module to converts path separators for the
tool (not the tool's arguments).

https://github.com/firebase/quickstart-unity/issues/379

Bug: 134758901
Change-Id: If591a21ab2c02f5e0005a10d554f4fbbf1dae799

Android Resolver's artifact downloader script was failing if a
dependency in the graph did not specify a version for an artifact.
This commit makes it possible to handle empty version specifications
in dependencies.

In addition, this adds more information to conflicting package log
messages and eliminates the creation of copy tasks for output
files that already exist.

Fixes #227
Bug: 134571587

Change-Id: I81d52d40c2447b6a6bfba68621fbd4b254570850

It was printing out "Repo directory %s not found" rather than
including the missing directory name in the message.

Change-Id: I5777450ffd1aaa6be8bdb5cefe73d0edc3b32430

Unity 2019.x throws an exception when
BuildPipeline.GetPlaybackEngineDirectory() is called and the Android player
isn't installed.  The Android build target can't be selected if it's not
installed, so we shouldn't be polling the build system if the build target
isn't Android.  This patch disables build system property polling on assembly
load if the build target isn't Android.

Fixes #220
Bug: 134665717

Change-Id: I147e51a9c7740d2e21fdd376abd7e6b2e7cdc7dc

* Android Resolver: Fixed exception due to Unity 2019.3.0a4 removing
  x86 from the set of supported ABIs.

Change-Id: I8a8f3fd91083b7c20fe66b48dc53c19eb5d73f0e

Unity 2019.3.0a4 removes support for x86_64 builds, removing the enum
value UnityEditor.AndroidArchitecture.  This results in an exception
being thrown during resolution.

Bug: 134137796
Fixes #224

Change-Id: I210c05d1f4bc9aa521b9ed61ed13159e504dac42

* Android Resolver: Added support for ABI stripping when using
  mainTemplate.gradle. This only works with AARs stored in repos
  on the local filesystem.

Change-Id: I2e1f00d09e365ab3204767010931530ac3ef985a

This will does not support removing libraries for unused ABIs in
AARs fetched from remote repos when using Android Gradle plugin
2.x.x.

Also, fixed handling moved maven repos in the project.

Bug: 133528579
Change-Id: I7a6fd807a03c0de7393fa6ce0f116817b9252794

Change-Id: Ib83668dcec58429df602d0acc27d0a46283e9f10

VersionHandlerImpl.RunOnMainThread() is pretty handy for editor
plugins so this exposes it.

Bug: 133495435
Change-Id: I8c5f38bf5f53efb53bf4071fdcc264105d1fcccc

* Android Resolver: If local repos are moved, the plugin will search the
  project for matching directories in an attempt to correct the error.
* Version Handler: Files can be now targeted to multiple build targets
  using multiple "gvh_" asset labels.
* Android Resolver: "implementation" or "compile" are now added correctly
  to mainTemplate.gradle in Unity versions prior to 2019.

Bug: 112525947
Bug: 133243196
Bug: 131903659
Change-Id: I63de34783612d12cee4031033c0693ab3be289e5

Some developers move plugins around in the project breaking local
maven repo paths.  This commit falls back to searching for local
maven repos if the directory isn't found, warning the user of the
file referencing the broken directory link along with the new
path.

Bug: 112525947
Change-Id: Ibfc2bc231904ccf93919edd9b5c78d0814e3d28b

BuildPipeline.GetPlaybackEngineDirectory() was added in Unity 2019
to get the playback engine directory.  The Android playback engine
directory is required to determine the version of Gradle shipped
with the plugin so this does not work in Unity < 2019.

This patch adds a compatible but slower way to retrieve the
AndroidPlayer directory which also fixes the generation of Gradle
dependency inclusion statements in Unity < 2019

Fixes #213
Bug: 133243196
Change-Id: I455ec6de28900a31ea414bd1ff657404e611b0fb